The "abstract idea" of a cookie is an identifier that it lets a server consider requests within a larger series of requests by the same person, but the fact that it can do that at all also meant that it solved the whole "how do we know whether this user is logged in without every page request after login needing to be a POST that includes the user's name and password again".
The modern mobile ecosystem is selling games consoles when the nerds want mobile Unix workstations.
So how about we just stop making "mobile phones" and just sell what they are: pocket computers. And that name immediately tells legislators what's appropriate hardware control, namely: none. If you buy a pocket computer, you can now do with that computer whatever you want, and the company that makes the hardware has no say over that, and the company that makes the OS has no legal basis for locking you out of anything. And if those are the same company, then the EU can finally go "how about no, you get to break up or you will never sell anything in our market again".